Method for fabricating a gap type semiconductor substrate of red light emitting devices

Abstract

A semiconductor substrate for GaP type light emitting devices which includes an n-type single crystal substrate, an n-type GaP layer, and a p-type GaP layer formed on the n-type GaP single crystal substrate. The carbon concentration in the n-type GaP single crystal substrate is more than 1.0×10 16 atoms/cc but less than 1.0×10 17 atoms/cc. The n-type GaP single crystal substrate is obtained from an n-type GaP single crystal grown by the Liquid Encapsulation Czochralski method wherein B 2 O 3 containing water corresponding to 200 ppm or more is used as an encapsulation liquid.

What is claimed is: 
     
       1. A method for fabricating a GaP type semiconductor substrate of red light emitting devices comprising the steps of: growing an n-type single crystal containing more than 1.0×10 16  but less than 1.0×10 17  atoms/cc carbon by the Liquid Encapsulation Czochralski method using B 2  O 3  as an encapsulation liquid, wherein said B 2  O 3  contains at least 200 ppm water; and;   forming an n-type GaP layer and a p-type GaP layer successively on a semiconductor substrate obtained from said n-type GaP single crystal.   
     
     
       2. A method for fabricating a GaP type semiconductor substrate of red light emitting devices according to claim 1, comprising doping with sulfur said n-type GaP layer. 
     
     
       3. A method for fabricating a GaP type semiconductor substrate of red light emitting devices according to claim 1, further comprising doping with oxygen and zinc said p-type GaP layer. 
     
     
       4. A method for fabricating a GaP type semiconductor substrate of red light emitting devices according to claim 1, further comprising forming the n-type GaP layer and p-type GaP layer by liquid phase epitaxy. 
     
     
       5. A method for fabricating a GaP type semiconductor substrate of red light emitting devices according to claim 1, wherein a top surface of a GaP melt used in growing the n-type GaP single crystal by the Liquid Encapsulation Czochralski method is maintained at 1470° C. whie a GaP single crystal is grown with a rotating rod pulling the GaP layer single crystal out of a GaP melt.